To provide a new composition for improving or preventing symptoms of Parkinson's disease that has few side effects, and can be conveniently produced.SOLUTION: Provided is a composition for improving or preventing symptoms of human Parkinson's disease, multiple system atrophy or progressive supranuclear palsy, the symptoms including at least tremors and/or forward-bending posture, or gait disorder, comprising a hydrogen gas-containing gas as an effective ingredient.SELECTED DRAWING: Figure 2-1【課題】副作用の少ないかつ簡便に製造し得る新しいパーキンソン病の症状の改善又は予防のための組成物を提供する。【解決手段】水素ガス含有気体を有効成分として含む、ヒトのパーキンソン病、多系統萎縮病、又は進行性核上性麻痺の症状、例えば少なくとも振戦及び／又は前屈姿勢、或いは歩行障害を含む症状を改善又は予防するための組成物。【選択図】図２－１
